Installation
•Do not start the motor more than six times per hour. Short cycling the tower will cause fuses, breakers or O.L.s to operate and will decrease motor life.
When using a two-speed starter:
| • Motor rotation must be the same at slow speed and high speed. | ||
| • Single winding motor requires a starter with a shorting contactor. | ||
| • | ||
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| contactor. | |
| • | All | |
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| when switching from high speed to low speed. | |
| • | Do not start the motor more than six times per hour (each low | |
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| speed start and each high speed start count as one start). | |
| When using a VFD: | ||
| Before beginning, ensure that the motor is rated for “Inverter Duty” | ||
Note | |||
per NEMA | |||
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| • | Set the VFD solid state overload protection to 119% of motor | |
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| nameplate amps and set “maximum current parameter” in the | |
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| VFD to motor nameplate amps. “Maximum current parameter” will | |
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| reduce fan speed and limit amp draw to nameplate amps during | |
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| cold weather operation. If furnished with a mechanical O.L. set this | |
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| at 110% over motor nameplate amps. | |
| • Motor rotation must be the same in both VFD mode and | ||
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| mode. | |
| • If cable distance between the VFD and motor is greater than 31m | ||
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| feet a DV/DT output filter is recommended to avoid damage to the | |
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| motor. 31mº distance is based on our field experience, the VFD | |
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| manufacture may state different distances and distance does vary | |
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| depending on the VFD manufacture. | |
• Program the VFD for variable torque output. Flux vector and con- stant torque modes may damage the gearbox.
• Do not start and stop the motor using the safety switch at the motor. If the drive is being commanded to run and the load side is cycled ON and OFF with the safety switch this may damage the VFD.
Using a VFD in cooling applications has advantages over traditional single or two speed motor control. A VFD can reduce the cost of electrical en- ergy being used and provide better temperature control. In addition, it reduces the mechanical and electrical stress on the motor and mechanical
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